FIELD OF THE INVENTION
The present invention relates to a valve timing control device for controlling timings of opening and closing an engine valve during the engine operation.
There is known a valve timing control device of the type, which is disposed between a rotary element rotatively driven by a crank shaft of an internal combustion engine and a cam shaft for actuating an engine valve, i.e., intake or exhaust valve. The valve timing control device is adapted to vary timings of opening and closing the engine valve by rotating the cam shaft relative to the rotary element.
Japanese Patent Application First Publication No. 8-121123 discloses a valve timing control device including a housing rotating with a rotary element driven by a crank shaft of an internal combustion engine, a rotor rotating with a cam shaft and vanes extending from the rotor. The vanes define a plurality of hydraulic fluid chambers within the housing. The device also includes a mechanism for supplying a hydraulic fluid to the chambers and discharging the hydraulic fluid therefrom. The housing and the rotor are relatively rotated by a difference of the fluid pressure within the chambers. Fluid communication between the mechanism and the chambers is established via fluid passages formed in the rotor and fluid passages formed in the cam shaft or a rotating support fixed to the cam shaft and the rotor. The rotor has an axial end face mating with an axial end face of the cam shaft or an axial end face of the rotating support. The fluid passages of the rotor and the fluid passages of the cam shaft or the rotating support are open to the corresponding axial end faces, respectively, and in axial alignment. Fluid communication between fluid paths of the mechanism and the fluid passages of the cam shaft or rotating support is established between an outer circumferential surface of the cam shaft or rotating support and an inner circumferential surface of a journal supporting the cam shaft or the rotating support.